JP2718676B2 - Virtual memory dump processing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Overview] This is a processing method that enables parallel execution of a dump for saving the contents of virtual storage when an error occurs during execution of a computer program, and execution of an interruption program. When an error occurs, a display indicating that the content needs to be saved is attached to the page existing at that time, and the program execution is immediately resumed thereafter. The contents of the page with this display are dumped in parallel with the execution of the program. With this processing method, the program interruption time when an error occurs is extremely short, and the utilization efficiency of the computer is improved. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a processing method for dumping stored contents when an error occurs in a computer program, and more particularly to a processing method for enabling a dump and execution of an interruption program to be performed in parallel. Especially when many so-called tasks such as a computer of an online system are executed in parallel, if any program error is detected in the task of the application program being processed online, the processing of the task is generally performed. Although tasks must be interrupted, tasks that are being processed in parallel can be continued, so it is desirable to continue execution immediately. On the other hand, since the contents of the storage space at the time of occurrence of an error are the main data for searching for the cause of the error, it is necessary to dump and save the contents. [Prior Art] FIG. 3 is a block diagram showing a configuration example of a computer of a virtual storage system. The processing device 1 is connected to the main storage device 2 and has a function of accessing the storage area, and executes a program loaded in the main storage device 2. The processing device 1 is connected to an external storage device 5 composed of, for example, a magnetic disk storage device or the like, and loads a required portion from the program and data stored in the external storage device 5 into the main storage device 2 for processing. In the case of the virtual storage system computer, a required page of a virtual storage space including a program and data for performing required processing is held in an external page file 7 of the external storage device 5, and the required page is stored in the external page file 7. The data is loaded into a real page of the main storage device 2. Execution control of the loaded programs and access to the data are requested by designating the logical addresses of the virtual space from those programs, and are generated by the address translation mechanism of the processing device 1 as instruction addresses or instruction operand addresses. The address conversion for converting the address to the real address of the real page 10 is executed, and the actual access to the main storage device 2 is executed using the real address. For such address conversion, for example, an address conversion table group for each virtual space is constituted by one segment table 14 and a page table 15 indicated by a pointer of each item of the segment table 14. In each page table 15, each item corresponds to each logical page, and when a real page 10 is allocated, holds a pointer indicating the real address thereof. If no real page is assigned, the page invalid bit of the item is set to 1 and the value of the pointer is set to 0. When an access request to a logical page having a page invalid bit is detected by the address translation mechanism of the processing device 1, a so-called page fault interrupt occurs, a paging management program is executed, and the external page file 7 stores the logical page of the logical page. If the contents are stored (page-out), a free real page in the main storage device 2 is selected and the page is loaded (page-in). If there is no free real page, an appropriate real page is selected, and if the content is updated, it is written out and saved in the external page file 7, and the real page is made empty. Used for page-in as described above. In each virtual storage space, an external page management table 16 is provided on the main memory to manage pages paged out to the external page file 7. The external page management table 16 associates each item with a logical page similarly to the page table, and holds a page address on the external page file 7 in an item corresponding to a page paged out to the external page file 7. To When an error is detected in a program executed in a certain virtual storage space and the execution of the program cannot be continued, a predetermined error processing routine performs the processing of the contents of all pages having valid information of the virtual space. Is output to the dump file 8 of the external storage device 5. If this program is executed in parallel by multiple tasks, even if an error occurs in one task, processing of other tasks can generally be continued, so the error handling routine completes the above dump processing Then, the execution of those tasks is immediately resumed and continued. Here, the error processing routine executes the dump processing, for example, as shown in the flowchart of FIG. That is, when the page address is set to the address of the first logical page in the virtual storage space and the processing is started, the page invalid bit is set according to the contents of the required page item of the page table 15 in the processing step 20 in FIG. If not, there is a real page, so the contents of the real page are transferred to a predetermined buffer in processing step 21, and the data in the buffer is output to the dump file 8 in processing step 22. If there is no actual page, the process branches to processing step 23, and refers to the external page management table 16 having the item of the corresponding page. The buffer is read from the page file 7 and when the reading is completed, the contents of the buffer are output to the dump file 8 in a processing step 22. If the output is completed or if it is determined that there is no valid page because there is no external page, it is determined in processing step 25 whether or not this space is the last page. Processing step 26
To advance the page address and return to processing step 20,
The above process is repeated for the next page. [Problems to be Solved by the Invention] When an error is detected in the execution of the program as described above, after dumping the information of the virtual storage space,
The execution of the program is resumed, but the dump process requires one or two transfers of input / output data to / from the external storage device for each page, as is apparent from the above-described process flow.
As is well known, such data input / output takes a very long time when viewed in the order of the execution speed of the processing device. For this reason, there is a problem in that after the error is detected, the time during which the substantial processing cannot be performed until the execution of the program can be resumed becomes longer. [Means for Solving the Problems] FIG. 1 is a flow chart of a process showing the configuration of the present invention. The figure shows the flow of processing by the error processing routine before resuming program execution in the error-occurring virtual storage space.
35 is a processing step. [Operation] When an error occurs due to the execution of a program, the program is stopped, and the error processing routine identifies the presence or absence of a real page by a page table in processing step 30 in FIG. In processing step 31, a predetermined display is made for the item in the page table. If there is no actual page, the external page management table is referred to in processing step 32, and if there is an external page, the processing step
At 33, a predetermined display is made on the table. In the processing steps 34 and 35, it is determined whether or not the page is completed. If the above processing is completed for all pages in the storage space, the execution of the program interrupted by the error is resumed. The dump processing of the page with the display is performed in parallel with the execution of the program and is saved before the page content is updated. As described above, without waiting for data input / output with the external storage device,
After a relatively short processing of only the display setting, the execution of the program is resumed. [Embodiment] When an error occurs during execution of a program, the program is stopped and an error processing routine is started. In the error processing routine, when a page address is set to the address of the first logical page of the virtual storage space in which the error has occurred and processing is started, the presence or absence of a real page is identified by the page table 15 in the processing step 30 of FIG. If there is a real page, the page invalid bit of that item in the page table is set to 1 in processing step 31. However, this page needs to be dumped by storing the pointer indicating the real page in the original state. It shall be an indication of that. If there is no real page, the external page management table 16 is referred to in the processing step 32, and if there is an external page, the storage bit provided in the corresponding item of the table is set to 1 in the processing step 33.
To indicate that this page requires a dump. If there is no external page, it is assumed that there is no valid page. After the above processing, it is determined whether or not the page is completed in processing step 34. If not, the page address is advanced in processing step 35 and the processing returns to processing step 30, and Repeat the process for the page. When the processing of all pages is completed, the processing of the error processing routine is completed, and the execution of the program interrupted by the error is resumed. As described above, since only the control information setting processing that does not require any data input / output with the external storage device 5 as in the related art is performed and the execution of the interrupted program is resumed,
The time from the occurrence of an error to the restart of the program is significantly reduced, for example, from the order of minutes to the order of microseconds. When the error processing routine terminates the processing by resuming the interrupted program, the dump processing routine is started at the same time. The dump processing routine executes the dump processing of the page indicated by the error processing routine as shown in FIG. 5, for example, in parallel with other programs. That is, the dump processing routine starts from the first page, proceeds to processing step 56 if the storage bit is set in the external page management table 16 in processing step 50, reads the external page into the buffer, and executes processing step 57.
Reset the save bit with. If the storage bit is not set, the page table 15 is inspected in the processing step 51, and if the page invalid bit is on and there is a real page, the page invalid bit is reset in the processing step 52, and then the processing step 53
Copy the contents of the page to the buffer with. The content held in the buffer by any of the above is output to the dump file 8 in processing step 54, and when the output operation is completed, it is determined in processing step 55, and if there is an unprocessed page, the process returns to processing step 50. And the above processing is repeated. When the restarted program executed in parallel accesses the page where the page invalid bit is set and a page fault occurs, at step 40 in FIG.
The presence or absence of a real page is identified based on whether the pointer of the page table 15 is 0 or not. If there is a real page, the processing routine notifies the dump processing routine to dump the contents of the page in processing step 41, and ends after turning off the page invalid bit of the page table 15 in processing step 42. The processing routine is executed preferentially from the entrance of the start 2, the page contents are stored in the buffer in the processing step 53, and the output is started in the processing step 54. If there is no actual page, the external page management table 16 is checked in processing step 43 to determine whether the above-mentioned storage bit is set in the item of the relevant page. If the save bit is set, the external page is read from the external page file 7 to the real page in the processing step 44,
By setting the corresponding pointer in the page table 15 in the processing step 45, it is allocated to an unused page in the virtual storage space, and the execution of the program in which the page fault has occurred is continued. The read external page is stored in the external page management table 16
Since the save bit is displayed in the item, the original content is saved thereafter. If the storage bit is not set in the item of the external page management table 16 in the processing step 43, the normal page fault processing is started. [Effects of the Invention] According to the present invention as is apparent from the above description, when information on a storage space at the time of occurrence of a computer program execution error is saved, the time required for resuming execution of the interrupted program is significantly reduced. Thus, there is a remarkable industrial effect that computer utilization efficiency is improved.

[Brief description of the drawings] FIG. 1 is a flowchart of a process showing the configuration of the present invention, FIG. 2 is a flowchart of the processing of the restarted program, FIG. 3 is a block diagram of a configuration example of a computer, FIG. 4 is a flowchart of a conventional process, FIG. 5 is a flowchart of the processing of the dump processing routine. In the figure, 1 is a processing device, 2 is a main storage device, 5 is an external storage device, 7 is an external page file, 8 is a dump file, 10 is a real page, 14 is a segment table, 15 is a page table, 16 is an external page management table, 20-26, 30-35, 40-45, 50-55 are processing steps Is shown.

   ────────────────────────────────────────────────── ─── Continuation of front page    (56) References JP-A-62-65146 (JP, A)                 JP-A-60-91459 (JP, A)                 JP-A-59-2156 (JP, A)                 JP-A-61-52753 (JP, A)                 JP-A-60-83150 (JP, A)

Claims (1)

(57) [Claims] A program arranged in a virtual storage space is executed, the virtual storage space is managed by being divided into pages, and has predetermined page management information for managing the pages, and a predetermined error state is detected during execution of the program. If an error condition is detected in a computer that dumps the storage contents in the virtual storage space at the time of the detection to a predetermined storage device, the execution of the program that generated the error Is stopped, and the page having the valid information of the virtual storage space in which the program is located is identified by the page management information. For all the pages having the valid information, the dump designation is set in the page management information corresponding to the page. If a real page exists as a display to be displayed, a page invalid flag is set. If no real page exists, a save flag is set. By completing the configuration of the dump specified,
When the execution of the program is resumed and the dump process is started, when the access to the page for which the page invalid flag is set occurs, if the actual page exists, the program And then continue the process after clearing the page invalid flag and if the real page does not exist and the save flag is set, continue processing after reading the contents of the external page to the real page In the dump processing, in parallel with the processing of the restarted program, for each of the pages of the virtual storage space, when the save flag is set, the contents of the external page are dumped and output. Clear the save bit, and if the save flag is not set, clear the page invalid flag and download the contents of the real page. Virtual memory dump processing method characterized by flop output.